Stone basketing has become an integral part of everyday urologic practice. Many cases will prove to be straightforward with simple stone extraction occurring in a matter of minutes. However, surgical misadventures might occur, some of which have lasting consequences. For instance, avulsion of the ureter is one of the most serious complications of ureteroscopy. It requires open or laparoscopic intervention for repair. The best way for the surgeon to avoid serious complications is to prevent them. The present invention provides devices that help the surgeon prevent such complications.
The common treatment of kidney and ureteral stones is uretroscopy. In this method once the stone is seen through the ureteroscope, a mechanical basket is used to grasp the stones and remove them. If a stone is too large to be removed, it can be fragmented into smaller pieces with laser lithotripsy, and then the smaller fragments will be removed one at a time. Stone basketing has the potential to cause ureteral injury. Hart in 1967 and Hodge in 1973, both after difficult manipulation of a ureteral stone with Dormia basket, reported the first cases of ureteral avulsion. Ureteral avulsion is one of the most feared complications of ureteroscopy, and stone extraction devices are often involved. The greatest risk factor for ureteral avulsion appears to be attempts to remove a large stone with the use of excessive force especially in a ureter with stricture (narrowing of the ureter). In addition, basketing a stone in the upper third part or section of the ureter increases the risk of avulsion because the proximal ureter has less muscle support and contains a thinner lining of mucosal cells than the distal ureter. Extraction of impacted stones can also cause ureteral avulsion or stricture formation. Furthermore, the use of multiple wire baskets has also been implicated, particularly with regard to the size of the stone (>1 cm) and the distance the stone has to cross before exiting through the ureteral meatus. The injury is typically recognized immediately because the stone is often removed along with a segment of ureter.
Perforation and urinary extravasations may also happen during stone basketing while extracting stones impacted in the collecting system wall. When a perforation occurs, the procedure should be terminated. In this situation, no attempt should be made to advance the stone basket through the perforation to retrieve the stone because these attempts will likely further enlarge the perforation. Prevention is the best way to avoid such serious complications.
It would be helpful to the surgeon to have real time access to information regarding the resistive forces encountered by the basket. Thus, if the resistive forces are too high, the surgeon can alter how the extraction is being performed. This is not only applicable to retrieval baskets for kidney stones, but is applicable to a broad range of extraction devices and procedures, as will be disclosed herein. There is a need in the art for surgical apparatus for extraction of substances from within a human or animal body, wherein the apparatus provides information regarding the resistive forces acting on the portion of the apparatus serving to extract the substance.